Add russian language support

diff --git a/lang/ru.lua b/lang/ru.lua
new file mode 100644
index 0000000..992f339
--- /dev/null
+++ b/lang/ru.lua
@@ -0,0 +1 @@
+SafeAddString(ART_STABLE_MASTER_CAPTION, "Хозяин конюшни", 1)